Method for forming paper can bodies



Jan. 1, 1952 R. M. DUNNING Erm. 2,580,665

METHOD FOR FORMING PAPER CAN BODIES 4 Sheets-Sheet l Filed June 2, 1945llll Il Il Jan. 1, 1952 R. M. DUNNING ETAL 2,580,665

METHOD FOR FORMING PAPER CAN BODIES Filed June 2, 1945 4 Sheets--SheeI 2Jan. l, 1952 R. M. DUNNING I-:rAL 2,580,655

METHOD FOR FORMINO PAPER CAN BODIES 4 Sheefs-Sheei 5 Filed June 2, 1945Jan. 1, 1952 R. M. DUNNING ETAL 2,580,665

METHOD FOR FORMING PAPER CAN BODIES Filed June 2, 1945 4 sheets-sheet 4Patented Jan. l, 1952 METHOD FOR lrORMTNG PAPER CAN BODIES Robert M.Dunning and Reynolds Guyer, St. Paul, Minn.,. assignors. to WaldorfPaper Products Company, St.Paul, Minn., 'a corporationA of- MinnesotaApplicatie; .nine 2, 1945, serial rnrsaazfzoA Our invention relates toan improvement in method and apparatus for forming paper/can bodieswherein it is desired to produce can bodies at low cost and at highspeed.

VCans having 'at least the side Walls thereof formed of paper or similarmaterial have been constructed for a considerable number of years. Mostof these can bodies are vformed by spirally Wrapping paper to form atube to which endclosures maybe attached. While suchcan bodies haveproven satisfactory insofar as containing packaged products isconcerned. their manufacture has certain diiiculties. vIn the firstplace such tubes normally must be formed in long lengths and then cutinto smaller lengths, thereby requiring two separate operations. In thesecond place, it is usually necessary to either wrap a label on such acan body or else to print the body after formation thereof. Furthermoresuch can bodies often have spiral grooves extending about the same whichdetract from their appearance and strength.y v

It is theobj ect of the -present invention to produce can bodies out offiat sheets of paper stock.

This flat stock may be easily printed before theA bodies are formed,thereby obviating'the require: ment for a separate label. Furthermore,the'can bodies may be stored in flat form until they are desired, andthen quickly formed into tubular formation. As a result it is notnecessaryto maintain a large inventory of formed paper can bodies `whichrequire costly space to store before use.

A feature of the present vinvention resides in the formation ofcylindricalcan bodies by'bending a plurality of at lsheets into tubularformation with one sheet overlying the other. As aresult a cylindricalcan body may be formed .of a plurality-of laminationsof paper board'orthe like. .i l

A further feature of the present invention lies in the provision of acan body. constructed of sheets of paper board bentinto cylindrical formto provide a laminated body, vand'in so` placing the sheets that thebutt, edges of :the various laminations are-in angularly spacedrelationship.

An additional object of the present invention isfto produce a canbodystructure of a series of overlying sheets coated with a thermoplastic coating. Thus wijlenl the fiat lsheetshave been bent intocylindrical form andy are positioned in' overlyingv relationship,thesesheets may be adhered together by the-` application of heat andThese andjother'objects features of? 2 our invention will be moreclearly and fully set forth in the following specification and claims.

In the drawings forming a part of our specification:

Figure 1 is a perspective View of a can, the body of which has beenformed by our method.

Figure 2 is a sectional View through the can body showing theconstruction thereof.

Figure 3 is a View similar to Figure 2 showing the application of astrip of adhesive tape or the like to assist in holding the sheets inproper relationship.

Figure 4 is a sectional View through a modied form of can bodyconstruction.

. Figure 5 is a diagrammatic side elevational view' of our can bodyforming apparatus showing the construction thereof.

Figure 6 Ais an enlarged detailed view showing diagrammatically theforward end of the body forming apparatus.

Figure 7 is an enlarged view showing diagrammatically the intermediateportion of the can body forming apparatus.

Figure 8 is an elevational view showing in en- 25 larged form thedischarge end of the can body forming mechanism.

Figure .9 is a diagrammatic section on the line 9-9 of Figure 6. f

Figure 1'0 is a diagrammatic section on the line Figure 16 is adiagrammatic section on the line l 6-[6 of Figure 8. Y

Figure 17 is a diagrammatic section on the line ll--H of Figure 8. v

Figure 18 is a sectional view through the completed can body.

In lorder thatit bel clearly understood whattype of construction is tobe formed by the method and apparatus shown', typical construction isshown in Figures 1 through 4 of the drawings.

Figure 1 shows a ycan'` A' having a side wall B made of paper or similarmaterial which was'bent from .nat form into cylindrical form. The can Ais shown having metal ends Il and I2 which arecrimpedl onto the ends ofthefside Wall body B in the usual manner. The closure II may include alling aperture normally closed by a plug cap I3 if it is so desired. Canends of the type illustrated have been commonly used for a considerableperiod of years.

In order to show the construction of the side wall body A we have shownthis body in section in Figure 2' of the drawings. Figure 2 il.-lustrates an inner sheet I4 which is provided with butting longitudinaledges I5 and I6. This inner sheet I4 is encircled bya second or outersheet I'I having butting longitudinal edges I9 and 29. The sheets I4 andI'I are secured to gether by any suitable means such as the layer ofthermoplastic adhesive 2l between these sheets. Other adhesive couldlikewise be used but the thermo plastic adhesive isv to be preferred.

In Figure 3 of the drawings 'I'disclose the can wall body B which isidentical with that shown in Figure 2 of the drawings, except that apiece of adhesive tape22 is provided over the butting edges I9 and 260i,the outer sheet I1. This tape 22 may be paper tape, bearing, a suitableadhesive, may be transparent tape, or may be pres'- sure sensitive tapeif it is desired. Figure 3 merely illustrates the manner in which such atape may be used if it is desired.

Figure 4 ofV the drawings showsV a modified form` of constructionillustrating the manner in which a. wall body having` three plies may beconstructed, if desired. In this type of` construction C the inner sheet23 is folded. atv 24 and 25 along parallel lines so that thelongitudinal edges 26 and. 21, thereof may overlie portions of theintermediate section of the` sheet. In other Words, the sheet is diivdedinto three panels comprising an intermediate panelY and two end panelsfoldably connected thereto along parallel fold lines. The endpanelsareof.; about one-quarter the area of the intermediate panel sothat when thev inner sheetis curved as.V illustrated in Figure 4, the.outer. panels 26 'and. 2l will form a substantially semi-circular doublesheet.

The outer sheet 29 of.. the can wall body is a central panel 30 andtwoendpanels 3| and 32 connected thereto along parallellinesoffold.

33 and 34.. These endpanels 3I and.. 32 comprise approximatelyone-quarter ofthe area of the panel 30so that when the outer sheet 29 isfolded as illustrated in Figure 4 the panels 3I and 32. form asubstantially semi-circular double thickness portion.

When the two sheets 23 and 29 are folded as shown the marginal edges 35and 36 of the panels 26 and 2.1 respectively, abutl the vedges 3l and 39of the panels 3| and 32. Accordingly a can bodyV is formed of threethicknesses of material which has no raw edges exposed either to theinside or to the outside of the body.

It will be noted that the can body material forming the liner of thewall is provided with two abutting folds 24 and 25, while the outercovering sheet 29 is likewise provided with two abutting folds 33 and34. exposed to the outside In illustrating andy describing the.formation.

of they can bodies, thestructure shown in Figure V3 has been used as. anexample. The: struci-i ture shown in Figure 2 is identical with thatshown in Figure 3, except that the tape overlying the butting edges ofthe outer lamination is omitted. Similarly the construction shown inFigure 4 may be folded on the same mechanism as is used for folding thecan wall B. In order to produce the wall C it is necessary to start theprocess described with sheets folded at 24, 25, 33, and 34. This foldingoperation may be separate from the operation shown in the drawings ormay beV employed as a primary step in the 4production of the can wallbodies illustrated. The; manner ofi folding inwardly the ends of thelbodysheetsis well known in the art and maybe accomplished on foldingmachines well known to the trade.

With referencenow to Figures 5 and 6 of the drawings it willbe notedthat the inner sheets I4- are stacked in feeding position in engagementwith a suitable sheet feeding apparatus indicatedV by the numeral 40.This feeder 40 feeds each sheet successively beneath the sheet foldinghorn 4I. The folding horn 4I may comprise a series of spaced bars orwires, but is shown in its simplest form as comprising a sheet of metalor the like having downwardly and inwardly turned marginal. edges 42thereupon. The mainbody of the folding horn 4I acts as a form aboutwhich vthe sheet is folded. The marginal edges 42 engage beneath themarginal edgesof each successive sheet I4 so as to fold the sheet to theshape of the folding horn 4I. As each sheet I4 enters the folding hornat its inlet end 43 the sheet is engaged by a lug 44 mountedguponanendless conveyor belt or chain 45, This lug 44 moves the sheet I4longitudinally of the folding horn 4I, the edges 42 of the horn actingto bendthe sheet into cylindrica l form asv it progresses. The lugs 44are spaced and are synchronized with the feeding mechanism 40. Thefeeder 40 acts to urge the sheet into the folding horn far enough topermitthe same to be engaged by the lug.

Figure9 indicates the position of the sheet at thevlinev 9-9 of Figure6. It will be noted that the sheethas been bent from its flat conditionin which itwas stacked to slightly bent form. The sheet is`heldagainstthe folding horn by any suitable. means such as by guideswhich are notV illustrated, or" may beheld in place merely by contactwith the endless belt or chain 45.

A folding horn 4I is supported by an inner tubular Vsupport 46 which isof a cantilever type. The inlet end 'of the support 46 is attached toany suitable supporting frame, While the outlet or discharge end of theapparatus is preferably entirely unsupported.

Figure v1() illustrates a successive step in the folding operation, thisligure being a section at the line I0--I0 of Figure 6. As will be notedin Figure l0 the folding of the sheet I4 has progressed considerablyfrom the position of the sheet shownhin Figure 9. In the position shownin Figure 10, the inner sheet I4 has been raised about one-quarter ofits final circular form. The

sheets I4 are preferablysupplied in position to travel longitudinally of the grain of the paper as the sheets bend more easily with the grainrunning axially with the bend. The sheet continues to be driven by thelug 44. The center of the folding horn 4I may be slotted as indicated at4T if it is desiredso that the extremity of the lug may extend wellabove the level of the sheet I4.

the sheetzbythelu. 1"

Figure 11 of the drawings illustrates a later step in the foldingoperation, this view being a section on the line II-II of Figure 6.V Atthis point of the bending operation the sides of the sheet I4 extendalmost vertically and thus the sheet is wrapped almost intosemi-circular formation Also shown in Figure 11 is the rst view oftheouter lamination I1. This sheet I1 is positioned above the centersupport 46 and is later folded about the inner sheet I4 in such a Way asto overlie the rbutt joint between the longitudinal edges I5 and I6 ofthe sheet I4;

The sheets I1 are stacked in sheet feeding position above the level ofthe support 46 and are fed by the sheet feeding mechanism 49 into theinlet end 50 of the folding horn 5I. The folding horn 5I is arrangedl tofold the sheet I1 to overlie the sheets I4.

- The folding horn 5I is shaped somewhatsimilarly to the folding horn.4I, but it is inverted relative thereto. `The folding horn 5I` may bein the form of spaced bars or wires, but is shown in sheet formation.The folding horn 5I includes downwardly and inwardly extending ilangededges 52 which form channels for re- 'ceiving the marginal edges I9 and20 of the sheet I1.

A conveyor 53 is supported above the folding horn 5I to move the sheetsI1 along the folding apparatus in unison with the sheets I4. Theconveyor 53 is provided with a series of spaced lugs 54 thereupon whichextend through a central slot 55 in the folding horn 5I. These lugs 54are designed to engage the rear edge of one ofthe vsheets I1 as thesheet is inserted into the entrance end 5I) of the folding horn 5I bythe feeding mechanism 49.

As will be noted in Figure 12 of the drawings when the sheet I4 iswrapped about slightly more than one-half the circumference of acylinder the sheet I1 has been folded partially. The sheet I1 is carriedalong above the sheet I4 and is positioned sufficiently above the sheetI4 to permit the ends of this sheet to extend somewhat above the levelof the support 46. The folding horn 4I is thus downwardly inclined asillustrated. If the support 46 is of suflicient length the sheet I4 maybe entirely folded before the folding of the sheet I1 is started, inwhich event the folding horn 4I need not be downwardly inclined.

vFigure 13 illustrates diagrammatically the condition of the sheets I4and I1 at a later stage in the folding operation. At this point thesheet I4 is almost entirely folded and the sheet I1 is wrapped aboutone-third of the circumference of a cylinder.

In Figure 14 the sheet I4 has been folded into circular form and theouter sheet I1 has been folded about one-half of the circumferencethereof. It will be noted that the center portion of the sheet I1 ismoving closer to the upper portion of the sheet I4 at this stage 4of theoperation.

In Figure 15 the sheet I1 is illustrated as about two-thirds foldedabout the sheet I4 and closely approaching the same. carried along bytheir respective conveyors which may be either in'timed relation orarranged with the sheet I4 somewhat in advance of the sheet I1.

With reference now to Figure 16 of the drawings it will be noted thatthe sheet I1 is almost completely folded about the sheet I4. At aboutthis stage of the operation the conveyor belt 45 Both sheets are beingassocies may terminate if desired and the two sheets may be carried inlunison' by the lugs 54 of the conveyor 53. Obviously in the event bothconveyors are in timed relation, both conveyors may continue beyondthispoint. However, in the event the sheet I4'is somewhat in advance of thesheet I 1 the sheet I4 will remain stationary for a short period' oftime until the sheet I1 is in registry therewith whereupon both sheetswill be carried in unison.

In order to adhere the two sheets firmly together the outer surface ofthe inner sheet I4 and/or the inner surface of the sheet I1 may becoated with a thermoplastic adhesive. When the sheets have been formedinto encircling formation with one sheet bound tightly about the otheras illustrated in Figure 17 of the drawings, these sheets maybe heatedand pressed together so as to form a tight bond. This may beaccomplished by any suitable means such as by providing a partition wall56 inthe tubular support 46 and in providing steam through any suitableinlet such as the steam pipe 51. As a result the entire free end of thesupport 46 is heated to a temperature suicient to soften or melt thethermoplastic of the coating. This action tends to adhere the two sheetstogether under heat and pressure so as to form a secure -bondtherebetween.

If it is desired a strip of tape may be applied over the butting edgesof the outer sheet I1 s0 as to hold the sheets in proper relation duringthe cooling of the thermoplastic' adhesive. This tape 59 is suppliedfrom a tape roll 60 and is applied by rollers such as 6I, one of which,62, may if desired form a cutting roller which will cut the tape to theproper length. Alternatively the'steam chamber 63 between the partition56 and the closed end 64 of the support 46 may be spaced fromthe'extreme end of the support so that the tubular body may be chilledbefore leaving the support 46.

As indicated at Figure 8 of the drawings the completed tubular bodiesare carried o' the end of the support 46 and into any suitable conveyingtrough 65 or the like, or may be delivered to asuitable bin.

It will be noted that in our method we first fold the inner sheet eitherpartially or entirely into cylindrical form and then fold the outersheet about the inner sheet in such a way that the butt joints of thesheet edges are in angularly spaced relation. The sheets are thensubjected to heat and pressure so as to adhere the same together,whereupon the tubular bodies may be released from the forming mandrelonto a suitable container or into a bin.

In accordance with the patent statutes, We have described the principlesof construction and operation of our method and apparatus for formingpaper 'can bodies, and while we have endeavored to set forth the bestembodiments thereof,lwe desire to have it understood that obviouschanges may be made Within the scope of 'w the following claims withoutdeparting from the spiritof our invention.

'We claim:

1. The method of forming a can body which includes the steps of moving.a flat sheet of a llength equal to that of the can body longitudinally.andlsimultaneously folding the sheet about a longitudinal axis, movinga, second sheet longitudinally and simultaneously folding the same abouta longitudinal axis, the second sheet being 7` foldedl about the firstsheet,A sheets iny tubular form.

' 2. Thev method, of forminga can bodyof thermoplastically coatedsheets, havingv folded op;- nos'ed marginal ends. the method consistinsQi. folding one sheet into tubular form with the 'folded ends thereofoutermost, folding a,` second sheet into tubular forni to` encircle thefirst sheet,v the folded ends thereof being innermost and abuttingrelationwith the, marginal ends of the rstsheet, and applying heat andpressure to the sheets to adhere the same together.

The method of formingv tubular walisfront spaced fiatv sheets of alength equal tothelength anni ademe said.

o fl the desired can body consisting-,in folding one4 sheety intotubularform so that` therends thereof are arranged in abuttingrelation.k moving, said.

sheet"longitudinally during the. folding` operation, moving a secondsheet, in timed-l relatiqnA to said rstsheet, folding thesecond sheetvto en close the first sheet so that the ends ofthe second sheet arearranged in` abutting relation,l and securing the sheets together. I Y

4. The method of forming4 atubularbody from a pair or" flat sheets of alengthequalvto the de,- sired length of the tubular body, the methodcon;-V sisting in moving one sheet longitudinally and simultaneouslyfolding the sheet into tubular form with the ends thereof abutting,movingwa second sheet in timed relation with the first sheet and `withthe ends thereof in registry, foldf ing the second sheet to overlie theabutting ends ofthe first sheet and to enclose the same, and securingthe sheets together.

5. The method of forming atubular body from a pair of flat sheets of a`length equal, to the.v

length of the tubular body, the method4 consist: ing in moving one sheetlongitudinally andV fold;- ing the ends thereof Yupwardly to form atubular body, moving a second sheet in timed relation withthe firstsheet so that the ends ofthe sheets are in registry, folding the ends ofthe second sheet downwardly to enclose the first sheet, and securing thesheets-in tubularform.

6. The method oflforminga/ can'body from a pair of sheets of alengthequal-to the length of the tubular body, the method oonsisti-nginfolding the. ends of the sheets-upon themselvesto provide sheets ofdouble. thick-ness yat theends', moving one sheet with the folded ends.under1y ing the adjacent portionL of the sheet,.folding the sheet intotubular forni so. that the foldedvv ends thereof lie outwardly ofthe.reniainderof, the sheet, movinga second sheet in timedrela,- tion tothe rst sheet, folding the second sheet with the folded edges thereofinnermost into.

tubular forni, the folded endsof vthe twosheets,v

forming an intermediate layer, between the remaining portions of the twosheets.

7. The method of forming a can body from` a,

pair of sheets having the longitudinal edges.V

thereof folded along parallel fold lines upon, the adjacent portionofthe sheet, folding one sheetA into tubular form with the fold linesthereof,4 in abutting relation, and with the folded ends, of, the sheetlying outwardly of the remainder ofj the sheet, folding a. second sheetinto tubularrfornr to enclose the first sheet withl thej fold'lnesthereof in abutting relation andthe folded ends thereof lying inwardlyofthe remainder of* the sheet, the folded ends ofA the two sheetsforming intermediate iayerbetween the remainder oil the sheets; -1

of the sheet, folding the second sheet into tubular,

forml with the fold lines thereof abutting and with the ends thereoflying inwardly of the re.-y

mainder of the sheet, the folded ends, of; onesheet substantiallyabuttingv the folded, ends4 of the other. sheet to form a substantiallycontinuous` intermediate layer betweenV the remaindexs. of; 'the sheets,

9. The'mcthcd o fyforming a can body from, a pair of sheets, whichincludes the steps of fold,- ing the` endsA of the sheetsalongparallel,fold lines so that they overlie adjacent portions` of the sheets,folding one sheet into; tubular form with the fold lines thereofabutting. and with the, folded ends lying outwardly of the remainder.ofthe sheet, folding, the second sheet into tubu lar form with the foldlines thereof abuttingv and with the ends thereof lying inwardly of there mainder of the sheet, the folded ends of one sheet.` substantiallyabutting the folded ends of theI other sheet to form a substantiallycontinuousintermediate layer between thel remainders,

of the sheets, and securing the; sheets inthis. tubular form.

10. The 4method of forming a hollow tubular wall which comprises movinglongitudinally a.

the last named series about a longitudinal axis.:

andzabouta sheet of the first named series withA the; ends of theconcentric sheets in registry,y

and adhering the sheets together.

- 11. The method of forming hollow tubular-crmY bodies fromthermoplastically coated flat sheets which includes the steps of movinglongitudinallyA a rst series of flat sheets-in spaced relation. andsimultaneously folding the same into hollowI tubular'form about alongitudinal axis.l moving longitudinally a second series of flatsheets.- and simultaneously folding the, second sheets into hollowtubular form about a. longitudinal axis: and, about thev firstmentioned'. sheet, the movement being timed to register the. ends,l ofthe. sheets, and applying heat and pressure to said sheets tov adherethe sameI together whilein hollow4v tubular finished form.

ROBERT M, DUNNING. REYNOLDS GUYER.

REFERENCES, CITED Thefollowingreferences are ofrecord' in the l'e oflthis patent:

